The present embodiments relate to operation of a magnetic resonance tomograph having at least one receiving antenna, at least one converter device for analog/digital conversion and a programmable computing device.
Magnetic resonance tomographs have a body coil and/or a plurality of local receiving antennas or local coils for receiving magnetic resonance signals. After reception, these signals are processed, and information obtained from the signals is made available to a data processing device in order to generate the respectively desired data records (e.g., images or 3-D data records).
One or more signal distribution devices may supply a particular number of analog input channels to a particular number of analog output channels during analog signal selection or signal combination. These analog output channels are supplied to a converter device that carries out analog/digital conversion. In this case, for example, a frequency shift to an intermediate frequency may be carried out before the analog/digital conversion. In this case, the analog/digital conversion is carried out continuously with predefined clocking.
The digital signals are supplied to a digital receiving device that processes said data further and extracts information from the data. The information is made available to the processing device. In this case, the digital data is processed in the digital receiving device in a sample-synchronous manner with the analog/digital conversion in the converter device. Therefore, at least parts of the data processing in the digital receiving device is to be carried out in hard real time with a maximum response time of half a clock length of the analog/digital converter. In order to achieve this, digital receiving circuits are implemented as hard-wired circuits or programmable circuits.
The digital receiving device, for example, carries out the preprocessing in this case, during which the received signals are demodulated (e.g., the relevant information is obtained from the signals). The volume of data is reduced in the digital receiving device by “punching out” only the data for the required measurement periods from the useful data. The data reduced in this manner are then made available to the data processing device via a buffer.
The method for receiving the signals from the magnetic resonance tomograph is therefore relatively complex and requires a large part of the data processing to be carried out in hard real time with very short response times. On account of these requirements, a conventional receiving method may be used only on specific complicated hardware.